{
  "eventId": "GRB 250221A",
  "subject": "GRB 250221A: GRANDMA/TAROT Detection",
  "bibcode": "2025GCN.39417....1M",
  "format": "text/plain",
  "circularId": 39417,
  "submitter": "Heather N. Muenter at UMN <hmuenter000@gmail.com>",
  "body": "H. Muenter (UMN), F. Magnani (CPPM), S. Antier (OCA/IJCLAB), Y. Rajabov (UBAI), C. Andrade (UMN), A. Klotz (IRAP), C. Limonta, Q. Andre, A. Durroux (OCA),  M. Coughlin (UMN),S. Karpov (FZU), P. Hello (IJCLAB), P-A. Duverne (APC), T. Pradier (Unistra/IPHC), N. Guessoum (AUS) on behalf of the GRANDMA collaboration:\n\nWe imaged the field of GRB 250221A detected by SWIFT (GCN 39396) with the TAROT robotic telescope located at the European Southern Observatory, La Silla observatory, Chile.\n\nThe first image was taken 45 s post T0 and without filter is trailed (see the description in Klotz et al., 2006, A&A 451, L39). We detect the UVOT optical transient at r-mag 17 +/- 0.1 mag, 1.95 min post T0. We continuously detected the source for the first 30 min.\n\nAll the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). Images obtained in Johnson Cousin filters were calibrated using the Gaia DR3 and PS1 catalog.\n\nWe use the SkyPortal application (skyportal.io) to monitor our observational campaign (Coughlin et al. 2023). \n\nGRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).\n\n",
  "submittedHow": "web",
  "createdOn": 1740193244714
}